Electric plug lock



J. G. GUINN Jan. 1l, 1938.

ELECTRI C PLUG LOCK Filed July 2, 1956 J J 6 WM Patented llan., 11, 1938 ammi 2 Claims.

.This invention relates to detachable electrical connectors and has for its primary object to provide means for detachably locking the parts of the connector together.

A further object of the invention is to provide a connector composed of intertting parts and means for automatically locking the parts together which is released upon turning one of the parts a quarter ci a turn.

Another object of the invention is to provide a device of the above-mentioned character which is simple and durable in construction, reliable and eii'icient in use and inexpensive to manufacture.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawing, forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a longitudinal sectional view of the connector,

Fig. 2 is a similar view taken at right angles to the section of Fig. 1, Y

Fig. 3 is a section taken on line 3-3 of Fig. l,

Fig. 4 is a section taken on line 3 3 of Fig. 1, with the plug member rotated through an angle of 90 degrees. with respect to the socket member,

Fig. 5 is a section taken on line 5-5 of Fig. 2.

In the drawing, wherein for the purpose of illustration, a preferred embodiment of the invention is shown, the numeral 5 denotes the socket member of the connector comprising a tubular body 6 having a screw-threaded base 'l extending from one end. The plug member 8 includes a body 9- adapted to slidably fit in the body of the member 5 and extending from the end of the body 9 is a central shank it having a contact I! on its end adapted to engage the spring i2 which connects with the central contact I?. of the base The shank l@ is rectangular shape in cross section and opposite sides of the shank, intermediate their length are recessed, as at i4, adapted to receive the spring contact arms I5 when the niembers 5 and S are intertted together. The contact arms I5 are V-shape having one end attached to the inner wall oi the base 'l and their opposite end free to spring into engagement with the recesses ld and establish contact with the contact strips l5 lining the bottom of the recesses. The outer end of the body 9 is provided with a transverse rib i? which supports the terminal screws I 8 and i9, the screw i3 being connected by the lead 2D to the contact strips l5 and the screw l5 connected with the contact Il through the lead 2|.

A lead-in conduit 22 is connected to the terminal screws and a cap 23 covers the terminal screws, being connected to the body 9 by screws 2Q. The inner walls of the body 6 are provided with 0pposed recesses 25, extending longitudinally of the body and secured Within the recesses, at one end, are spring guide strips 26, the outer ends of which are free to resiliently engage the sides of the body Q when the plug and socket members are fitted' together. The sides of the body 9 at their points of contact with the guide strips 25 are beveled, as at 2l, to facilitate insertion of the plug member in the socket member.

In operation, the plug member 8 is inserted in the socket member 5, being guided in its movement by the guide strips 26. The shank IB of the member 8 passes between the free ends of the contact arms I5, which spring into engagement with the recesses I4 in the sides of the shank, thereby locking the plug and socket members together. When it is desired to break the connection, the plug member 3 is given a quarter of a turn to dis-engage the spring contact arms l5 from the recesses I4, so as to permit withdrawal of the plug member from the socket member. Thus, it is seen I have provided a connector which is automatically locked when the parts of the connector are intertted together, which will prevent accidental breaking of the connection and yet may be readily disconnected when desired.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same and that certain changes in the shape, size and arrangement of the parts may be made without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, I claim:-

1. An electrical connector comprising a socket member, a plug member adapted to rotatably and` slidably fit in said socket member, said plug having a central reduced shank extending longitudinally from its inner end, said shank being square in cross section and having opposed longitudinal recesses in two sides of the shank, V-shaped contact arms having one end attached to the inner side walls of said socket member and their free ends extending in a direction towards the bottom of the socket member, and contact strips disposed in the recesses of said shank adapted to be engaged by the free ends of said contact arms when the plug and socket members are fitted together, said contact strips being released from engagement with said contact strips only upon rotation of said plug member through an angle of 90 degrees With respect to said socket member.

2. An electrical connector comprising a socket member, a plug member adapted to rotatably and slidably t in said socket member, said plug having a central reduced shank extending longitudinally from its inner end, said shank being square in cross section and having opposed longitudinal recesses in two sides of the shank, V-shaped con- 10 tact arms having one end attached to the inner side Walls of said socket member and their free ends extending in a direction towards the bottom of the socket member, contact strips disposed in the recesses of said shank adapted to be engaged by the free ends of said contact arms when the plug and socket members are fitted together and spring guide strips attached to the inner Walls of said socket member adjacent its mouth adapted to engage beveled shoulders at opposite sides of the plug for guiding the plug when inserted in the socket member and aligning the recesses of the shank With the Contact arms, said contact arms being releasable from engagement With said contact strips only upon rotation of said plug member through an angle of 9G degrees with respect to said socket member.

JAMES G. GUINN. 

